1. Field of the Invention
The present invention relates to a protective leg adapted to be attached to the bottom surface of an object such as furniture or electrical apparatus.
2. Statement of the Prior Art
Furniture, electrical apparatus and other fittings are provided on the bottom portions of their casing with fixed and protective legs. One of the first conventional examples of such protective legs is illustrated in FIGS. 6 and 7, in which A denotes a cylindrical leg body formed of a synthetic resin by way of example, B, a bottom plate, C, a cylindrical rivet portion housed in A and extending vertically from B along the axis of A, and D, a hole extending vertically through C. An extreme end of the inner face of the through-hole D is tapered off. On an extreme end of the portion C, there are radially formed longitudinally split grooves E of a given depth, in which a plurality of stopper pieces F are to be received.
As illustrated in FIG. 7, the extreme end of the rivet portion C is inserted into, and projects from a mount hole H formed in a plate-like bottom portion G of an object such as an item of furniture, and a pin I is driven into the through-hole D in the rivet portion C from its lower end, whereupon the stopper pieces F are enlarged outwardly from the peripheral edge of the mount hole H, so that the leg body A is fixed to the bottom portion G of that object.
According to another, or the second conventional example shown in FIGS. 8 and 9, a disc-like leg body A formed of a hard resin or the like is provided in its bottom portion with a circular recess B of a given depth, and includes an axial through-hole D for a tapping screw C, which through-hole is provided in its lower end with a recess E in which a head portion C1 of the tapping screw C is received. F is a disc-like rubber or felt member to be fitted into said circular recess B, which is centrally provided with a round hole G having a diameter equal to that of the recess E. A release sheet H is applied over an adhesive agent coated on the upper face of the rubber or felt member F.
During use, the release sheet H is first removed from the rubber or felt member F. Afterwards, the member F is adhesively bonded onto the circular recess B in the leg body A, the upper face of the leg body A is then brought into contact with the bottom portion of an object I to insert the tapping screw C into the through-hole D from below, thereby fixing the leg body A in place.
Referring to a further, or a third conventional example shown in FIG. 10, a cupped leg body A includes recess C in its bottom plate B, and a cylindrical member D axially extends from the bottom plate B with a hole E extending vertically therethrough. The upper end of the cylindical member D is longitudinally split at F, from which a plurality of stoppers G extend. It is noted that each stopper G is tapered off on its inner face. Further, an insert H to be fitted into the through-hole E in the cylindrical member D is provided at its lower end with a flange member I to be fitted into said recess C, which has an increased friction resistance and is elastic.
After the stoppers G of the leg body A have been inserted into a through-hole K formed in a lower panel J of an apparatus, the insert H is forced into the through-hole E in the cylindrical member D, whereupon the tapered inner faces of the stoppers G are enlarged by its upper end to fix the leg body A onto the lower panel J, while the flange member I is fitted into the recess C in the leg body A and projects downwardly from its bottom (see Japanese Utility Model Publication No. 54(1979)-21252).
Referring to a still further, or the fourth conventional example shown in FIG. 11, a cupped leg body A is provided on the upper face of its bottom plate B with an axially upright cylindrical member C including a hole D extending vertically therethrough. The member C is longitudinally split at E in its upper end, from which a plurality of stoppers F, each tapered of on its inner face, extend. Further, the member C is provided in its lower end with recess G. An insert H to be inserted into the through-hole D in the member C is provided in its lower end with a head portion I to be fitted into the recess G.
After the stoppers F of the leg body A have been inserted into a through-hole K formed in a lower panel J of an apparatus, the insert H is inserted into the through-hole D in the cylindrical member C, whereupon the tapered inner faces of the stoppers F are enlarged by its upper end to fix the leg body A onto the lower panel J, while the the head I of the insert H is fitted into the recess G in the leg body A (see Japanese Utility Model Publication No. 55(1980)-23404).
Finally, a still further, or the fifth conventional example is shown in FIG. 12, which includes a main leg body A in the cylindrical form, an inner cylindrical body B contiguous to a lower face of the main leg body A and vertically provided coaxially therewith, and a through-hole C formed in B, which is open at its lower and upper ends. Within a rivet member D extending upwardly from the upper face of such through-hole C, there is axially formed an insert hole F for a drive pin E in communication with the through-hole C, the inner face of said hole F being tapered off upwardly so as to decrease in thickness. Further, the rivet member D is radially provided with a longitudinally split groove G of a depth sufficient to reach near the upper face A1 of the main leg body A, thus defining a free end H. It is noted that, as shown by a dot-and-dash line, the drive pin E is coaxially positioned within the through-hole C prior to use, while the extreme end thereof is made integral with an entrance open end F1 of the insert hole F by way of a weak connection (not shown) with the base end thereof projecting downwardly from the lower face of the main leg body A.
The rivet member D of the main body A is inserted in a mount hole K formed in a bottom plate J of a piece of furniture so as to bring the upper face of the main leg body A into abutment against the bottom plate J. As the drive pin E is then driven into the insert hold F in the rivet member D, the weak connection is broken out so that the drive pin E moves into the insert hole F, while its extreme end slides over the tapered inner face of the free end H. In this manner, the free end H is enlarged outwardly, thereby fixing the main leg body A onto the bottom plate J (see Japanese Utility Model Publication No. 60(1980)-1288).
In general, such protective legs desirably prevent easy movement of electrical apparatus or other fittings so as to avoid accidents while exhibiting a rigidity sufficient to withstand the weight of electrical apparatus or other fittings.
However, although the first conventional example is capable of bearing the weight of the product because of the leg body A being formed of a hard synthetic resin, it is disadvantageous with regard to its ease of sliding and in that any vibration-preventing effect is minimal. Nor is any effect upon the prevention of floor damages to be expected.
The second conventional example example exhibits increased frictional resistance, since the leg body A is additionally provided on its bottom surface with rubber, felt and so on, as shown at F. With this embodiment therefore, some preventive effect upon the inadvertent movement or vibration of the object or the prevention of damage to a floor, on which the object is mounted, are expected. However, since the rubber or felt F is only bonded to the bottom surface of the leg body A by means of adhesives, it tends to be easily peeled off therefrom, when the object is forcibly dragged or strikes an obstacle, or owing to temperature conditions, it change thereof with time and the like. Especially in the case of soft rubber, it is likely to deform upon bearing a large weight, or the deterioration thereof with time, thus failing to maintain its initial performance. Felt makes the product very expensive.
The disadvantages of the third conventional example are that, since the insert H designed to enlarge the stoppers G and be fixed to the lower panel J is made integral with the elastic grounding member I of an increased frictional resistance, the grounding member I is immediately released from the bottom surface of the leg body A and the insert H is pulled out of the stoppers G, thereby disengaging the leg body A from the lower panel J, when the apparatus is dragged.
The fourth conventional example exhibits a disadvantage similar to that of the first conventional example due to the leg body A being formed of a hard resin or the like, and the fifth conventional example is disadvantageous in that it is of a complicated configuration which requires a complicated mold, thus resulting in a decrease in the productivity and a rise in cost.